So I've recently replaced the thermostat and done a heater core flush as well as a new blower motor on my 92 loyale and my heater just doesn't get warm any ideas why??

Still air in the system. Not sure if there's a burping procedure or if you just need to add more coolant

Get the car up to operating temp, and check the heater hoses. If one is hot, the other not, chancrs are its a blocked heater core. If tgeyre both hot, then your blend door isnt working. Meaning its not actually turning the heat on.

If one is cold, mark the cold one, then take the hoses off and flush water in thru the marked one with your water hose. This can sometimes unblock a stopped up heater core.

 

Also check the radiator hoses. If one is hot, the other cold, you have a bad t-stat. Yep that new t-stat. Subarus dont like aftermarket t-stats. If you suspect an air bubble. Park the nose uphill, on ramps, or jack it up before filling it with water.

+1 On the original Subaru thermostat,  I had the same problem but not anymore.

My guess is the heater core or the cables for the controls aren't adjusted right. I went through all the b.s on my hatch back trying to get the heater to work. Adjusted all the cables and flushed the heater core for 20 minutes going in the opposite direction of flow for most the time. Ended up pulling my dash and putting a heater core in now it's nice and toasty for winter. I haven't had a problem with after market thermostats. Just check where it opens and closes at in boiling water. My ej'd hatchback ran at the same temp with a aftermarket as it does with factory one i bought.

Also, if you are not the original owner of the car, then a previous owner may have used Bar's Radiator Stop Leak or similar product which are widely known to block or severely restrict the small coolant passages of the heater core in the ea81s and ea82s, not sure on the EJs.  If this is the case, then the only fix is to replace the heater core.  So if you check everything and flush everything and nothing seems to work, then you might consider replacement.